Composition or compound for brushes of dynamo-electric machines.



No 849,643. PATENTED APR-9,1907. 0. W. sPBIRs;

COMPOSITION OR COMPOUND FOR BRUSHES OF DYNAMO ELECTRIC MACHINES I APPLIOATIOH FILED JUNE 29.1905.

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- 1 VQENTOR UNITED srarns PATENT OlihiCE.

CHARLES \VILLIAM SPEIRS, OF BATTERSEA, LONDON, ENGLAND, A SSlGNOR TO TH E MORGAN CRUCIBLE COM PANY, L [M l'll ll), OF LON DON, EN GLAN D.

COMPOSITION OR COMPOUND FOR BRUSHES OF DYNAMO-ELECTRIC MACHINES.

a No. 849,643."

Specification o f Letters Patent.

Patented'April 9,1907.

Application filed June 29, 1905. Serial No. 267,662.

To all w/wm it Huey concern:

Be it known that I, (JiIAnLEs WiLLIAM Seems, a subject of the King of Great Britain, residing at Batter-sea Works, Battersea, London, England, have invented a new and useful Improved Manufacture of omposh tion or Compound ior Brushes of Dynamo- Elcctric Machines f or Bearings and for other Articles; and I do hereby declare that the following is a full, clear, and exact descri tion of the invention, which will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to the manufacture of a compositionor compound for brushes of dynamo-electric machines, for bearings, and for other articles, and relates to an improvement in the manufacture described in the specifications of my former applications, datci November 7, 1904, Serial No. 231,820, and May 22, 1905, Serial No. 261,690.

I In. my lormer application, Serial No.

231,820, above referred to, I described and claimed a commutator-brush formed of plumbago,(such as may be obtained from Ceylon and which is of such nature that when ground it is in the condition of small flakes,) the ground lumbago being treated with a glutinous su stance (such as gelatin in solution, containing one ound ofgelatin to one .hundred pounds ogw'ater and mixed with the ground plumbago in the proportion of one and one-half parts, by..weight, of the former to one part of the latter) and then subjected to great pressure v(for instance,

twenty tons per square inch) in a direction at right angles to that in which the current is to flow through the brush, whereby the ilakes will arrange themselves. with their planes parallel with the pressing-surface, so that a relatively large number ofcontacts between the flakes will occur in the thickness of the brush compared with the number of contacts between the flakes in the +5 lcngtlrof the brush, and in my former application, Serial No. 261,690, above reerred to, I described and claimed the method of manufacturing solid Stratified blocks of plumbago, consisting of grinding jecting it to such a high degree of pressure the crystalline or flaked natural plumbag0-' as'will cause the flakes to set thcn'iselves in stratified planes parallel to the plane of pressure.

1n the course oi numerous experiments which I have made in the manufacture of or other metallic substance, in a finelydivided state the electrical conductivity of such brushes or other .artic'les'can be increased and the wearing properties improved and that metallic surfacesv can be ormed upon or in connection with such articles which are continuous with the nonmetall1c(port1on of the articles.

Accoring to my invention the copper is first incorporated with the plunibago in a dry state, the plumbago being eferably in the form of a powder. which will; )Lass through a' sieve of about two hundred meshes to the linear inch, and the copper being of any dosired'grade according to the special purpose in view from the fineness, say, of line hour to that of the coarser grades of i'lourl The proportions may be varied according to the special purposes in view and al'soffr m1 point to point of the article. For instance, a layer of copper powder maybe placed on one face of thearticle, next to this a layer containing a small roportion of plumbago, and so on througliout the article as desired. Also in a commutator-brush, for instance, that -dge which first makes contact with segment might contain, sa sixty per cent. of copper, while the edge t at breaks contact can be without metal, and the intervening portion can be graded in layers with varying quantities of inetaL- The graphite and metal having been mixed together and a ranged in the desired manner the mass is subjected to a high pressure'say from fifteen to thirty tons per square inchin order to effect the thor-- ough union or solidification of the mass and so that any face or'layer whichjconsists of copper powder only will form a' continuous metallic face or layer in-the compressed artiole. When the material is compressed, the flakes of plumbago. will arrange themselves {in stratiijed planes on accountjof the nature of the plumbago as deseribed in my former l npplieat ions ahore referred to.

The pluinbago may he treated with a glul tinous substance or not, as desired The] mode of treatmentwith gelatin described in my said application, dated November 7, l 1904, Serial No. 231,820.

To illustrate my inven 'on, I append a sheet of drawings, in which---- 3 Figure I is a perspective VltW of a block of I; compressed 'ihnnhago and powdered metal 5 made in aerordnnw with my invention. Fig. 2 is a partial section,greatly magnified. taken in a plane parallel to the strata of the plumbaeo. Fig. 3 is a similar ViOW taken in a plane perpivnclicular to the strata of plumbago and showing the proportion of metal, varying from one edge of the block to the other. Fig. 4 is a View similar to Fig. 3, showing a hloek in wlirili several completely metallic layers extend througihout-the block.

In these figures, (1 a indicate the lakes of plinnba o, which are drawn as greatly magnified for the sake of rlearness, and b I) indirate dots whieh represent the metallic partieles.

in Fig. 3 a block is shown in which a continuons copper layer is shown on one side at I). and the succeeding layers of pluinhago and metallic particles contain varying proportions of the metal, the proportion of metal decreasing toward the other face of the block, as shown. Such a blot-k can be advanta- ,LIOUUSlY used for a eoinnlutator-brnsh. In Fig. =1- l. have shown several layers of metal only, as at (1, arranged at intervals 1 throughoutthe block. and on the outer fi -w;

thereof.

The composition hereinbel'ore tleserihed, in addition to its use for ilynamo-brushes, can

t be atlvantageously employed forthe manufacture of other articles, especially in eases Where a tough material with a good lubricatlug surface is desired-as, for instance, bear-- ings for shutting, plungers for the dasli'pots of electric-are lamps, and the like.

In this specification the word (r/upper" to be taken to include any equivalent met allie substance having; analogous proportion to copper for the purposes of the particular artiele in view.

Having now particularly described and ascertained the natureof my said invention and in what manner the same is to be performed, I. declare that what I claim is---- A co:nmntator-brush ermsistin; of cone pressed or crystalline phtmbago having ineorporated with it metallic copper 1n. f nelydivided condition, the t-lakes of pluni'lrago being arranged in stratified planes parallel to the plane of pressure, and the metallic parti cles being so arranged as to form at one face of the brush an uninterrruptied metallic surface. and being distributed through the mass in graduated proportions, the proportion of copper decreasing; toward the opposite l'aee of the )rush, substantially as described.

CHARLES WILLIAM SPEIRS.

Witnesses;

WILLIAM W ALTER Janus, A. ALnu'r'r. 

